What is phase modulation?

• A. A method that changes the frequency of the carrier wave
• B. A technique that alters the phase of the carrier wave
• C. A process that changes amplitude levels
• D. A method of enhancing audio clarity

Answer: (B)

Phase modulation is a technique that alters the phase of a carrier wave to encode information. By changing the phase at which the carrier wave is transmitted, a modulator can convey different data signals. This modulation method is key in various forms of communication, including radio transmission, where it can effectively transmit information over distances.

When the phase of the wave is altered, it results in a shift that corresponds to the data being sent. This allows receivers to detect the timing changes and interpret them as signals, making phase modulation a sophisticated way to manage the information flow.

Other options involve methods like changing frequency or amplitude, which are representative of different modulation techniques like frequency modulation and amplitude modulation. Phase modulation is distinct in its approach, focusing specifically on phase alterations, which sets it apart and plays a crucial role in certain communication systems. Additionally, enhancing audio clarity doesn’t specifically relate to the modulation technique itself but rather to the overall audio processing that may occur following modulation.